In an electronic throttle control system of an automotive vehicle internal combustion engine, the accelerator pedal is electromechanically, rather than mechanically, coupled with the throttle blade. An example is disclosed in commonly assigned U.S. Pat. No. 4,850,319.
The preferred electromechanical actuator is a unipolar stepper motor gearlessly coupled with the throttle shaft, with the motor controlled by an electronic controller in accordance with several inputs, one of which is from the accelerator pedal. The preferred controller is microprocessor-based, comprising a devoted microprocessor.
The electronic controller and the stepper motor operate from voltages which are appreciably less than that of the vehicle's electrical system, for example 5 VDC vs. 12 VDC. Accordingly, the incorporation of a suitable voltage regulator is conventional, and a standard integrated circuit device can be used for this purpose.
A conventional practice in a microprocessor-based system is to reset the microprocessor at power up by means of a reset pulse, and so it is also conventional for the standard voltage regulator integrated circuit to have a reset output which gives a suitable reset pulse to the microprocessor at power up. Failure to reset the microprocessor at power up can give rise to the exercise of improper control over the throttle blade.